Latching mechanism



March 22, 1966 c, CAIRELLI 3,241,870

LATCHING MECHANISM Filed April 4, 1963 2 Sheets-Sheet 1 INVENTOR. CARMENF. CAIRELLI ATTORNEYS C. P. CAIRELL! LATCHING MECHANISM March 22, 1966 2Sheets-Sheet 2 Filed April 4, 1963 INVENTOR. CARMEN P. CAIRELLI UnitedStates Patent 3,241,2270 LATQHTNG MECHANHSM Carmen P. Qairelli,Farmington, Conm, assiguor to M. H.

Rhndcs, The, Hartford, Conn, a corporation of Bellaware Filed Apr. 4,1963, Ser. No. 270,637 I 7 Claims. (Cl. 292-444) This invention relatesto new and improved latching mechanisms and more particularly to alatching mechanism of the type actuated by the angular displacement of arotary operator.

A principal aim of the present invention is to provide a new andimproved latching mechanism of the type described adapted for automaticactuation after a preselected time interval. A significant use of thepresent invention is for the automatic unlatching after a preselectedtime interval of the enclosure cap of an aerospace vehicle sent aloftfor the measurement of temperature, humidity or other phenomena, andfrom which onclosure scientific instruments are ejected for taking thosemeasurements. Therefore, the principal aim of the present inventionincludes the provision of a latching mechanism reliable under high Gloading and within abnormal temperature, moisture and humidityenvironments, which is compactly constructed for installation within theusual cylindrical enclosure of a rocket or other aerospace vehicle, andwhich is adapted for automatically unlatching an enclosure cap at apreselected and accurate time interval after the launching of thevehicle.

Another aim of the present invention is to provide a new and improvedlatching mechanism that can be conveniently actuated for providinghighly reliable operation even though the forces, frictional orotherwise, restraining the movement of the latching parts besubstantial.

A further aim of the present invention is to provide a new and improvedlatching mechanism of the type described having a pair of oppositelyextending latching parts that are simultaneously operated by angulardisplacement of the rotary operator and with minimum loading and wear onthe mechanical parts.

Other objects will be in part obvious and in part pointed out more indetail hereinafter.

The invention accordingly consists in the features of construction,combination of elements and arrangement of parts which will beexemplified in the construction hereafter set forth and the scope of theapplication of which will be indicated in the appended claims.

In the drawings:

FIG. 1 is a top plan view, partly broken away and partly in section, ofa preferred embodiment of the latching mechanism of the presentinvention;

FIG. 2 is a side elevation view, partly broken away and partly insection, of the latching mechanism installed in a cylindrical casing,showing the latching mechanism in solid lines in the fully withdrawnposition and a portion thereof in phantom lines in the fully extendedposition;

FIG. 3 is a section view taken along the line 3-3 of FIG. 2 of thelatching mechanism in the fully withdrawn position;

FIG. 4 is a section view similar to FIG. 3 of the latching mechanism inthe fully extended position, further showing a portion of the latchingmechanism in phantom in two intermediate positions;

FIG. 5 is a section View taken along the line 5-5 of FIG. 2 of thelatching mechanism in the fully withdrawn position; and

FIG. 6 is a section view similar ot FIG. 5 of the latching mechanism inthe fully extended position, further showing a portion of the latchingmechanism in phantom in two intermediate positions.

Patented Mar. 22, 1966 Referring now in more particularity to thedrawings, a preferred embodiment of the latching mechanism of thepresent invention is rigidly constructed with a frame having threeparallel mounting plates 10, 12 and 14 shown to be of generally circularshape for convenient installation within a tubular shell or casing 15.The end plate 14 provides a cap for the casing and upon removal allowsfor ejection, as by a loaded spring, of the contents within the casing.Such enables the casing to be used as a vehicle sent aloft withscientific instruments for measuring atmospheric phenomena as, forexample, a conventional rocltet-sonde vehicle sent aloft for measuringphenomena in the upper atmosphere.

Three transverse pillars l6 staked to the inner plate 10 provide formounting the central plate 12, and three cylindrical spacers 1? providefor mounting the end plate 14-. The spacers 18 have ends (not shown) ofreduced diameter threaded into the pillars 16 for rigidly securing theplate 12, and screw fasteners 19 (shown in section in FIGS. 3 and. 4)threaded into the outer ends of the spacers 18 provide for rigidlysecuring the end plate 14. Latching of the end plate 14 within thetubular housing 15 is provided by a pair of identical overlying latchingcatches or bolts, generally denoted by the numerals 2t and 22, stampedfrom sheet metal. The bolts have locking ends 24' projecting beyond theperiphery of the end plate 14 when the bolts are extended, as shown inphantom in FIG. 2, for receipt within diametrically opposed slotopenings in the tubular housing 15.

As seen in FIGS. 3 through 6, the bolts 20, 22 are radially slottedadjacent their ends for receiving a pair of inwardly extending studs 26staked to the end plate 14. The studs 26 provide closely fitting guidesfor the radial movement of the bolts with the enlarged heads 28 of thestuds retaining the bolts in their overlying relationship on the endplate 14. The bolts have enlarged central portions provided with racetracks shaped openings 3t) defined in part by pairs of oppositely facingshoulders 32 extending perpendicularly to the axes of movement of thebolts and in part by pairs of oppositely facing generally semicircular,concave end shoulders 34 bridging the shoulders 32.

For driving the bolts an operating shaft or arbor 40 is rotatablymounted eccentrically on the plates lltl and 12 about an axis extendingperpendicular to the planes of the fiat locking bolts. The shaft 40extends beyond the plate 12 and within the openings 30 midway betweenthe end shoulders 34. A mainspring 42 having its inner end secured tothe shaft and its outer end wrapped about a tang 43 inwardly extendingfrom the plate 10 provides a torsional bias on the shaft in thecounterclockwise direction (as seen in FIG. 1). The end of the shaft 40opposite the bolts is shown slotted to provide for winding themainspring in the clockwise direction as by a screwdriver. Inwardlyturned tangs 44 of the plate 10 provides stops limiting the expansion ofthe mainspring, and a thin sheet metal plate 46 overlying the mainspringand positioned between it and an enlarged shoulder 48 of the shaft 40prevents axial displacement of the mainspring.

Press-fit upon the shaft 40 between the plates 16 and 12 is a gearsector 50 and a stop 52 having two radially extending arms 54, 56adapted for engagement with the edges of a pie-shaped tang 60 formedfrom the central plate 12. The projection 54 engages one edge of thetang 60, as seen in FIG. 1, to provide a forward stop for the angularmovement of the operating shaft 46 and the projection 56 engages theopposite edge of the tang 60 to provide a reverse stop for the operatingshaft, the angular freedom of movement of the shaft 49 being 180degrees. The gear sector 50, on the other hand, is provided with teeththroughout an angle of substantially degrees.

By a mechanism, including an escapement generally designated by thenumeral 62, somewhat similar to a clock mechanism, a portion of theforward angular movement of the shaft 40 is restrained for movement at atimed rate. The ratchet wheel 64 of the escapement is operativelyconnected to the shaft by pairs of meshing gears 66 and 68 and 70 and72, and by a gear 74 adapted for meshing with the gear sector 50. As ina conventional clock mechanism, the ratchet wheel 64 and pinion 66 arefixed to a shaft 75 having reduced ends which are received for rotationwithin opposed openings in the plates and 12. In similar fashion, thegears 68, 70 and 72, 74 are rotatably mounted on the end plates;however, the openings 79 in the end plates for the shaft 77 supportingthe gears 68, 70 are elongated to provide for lateral movement of thosegears outwardly from engagement with the mating gears 66, 72,respectively. A pair of music wire cantilever springs 76 are riveted tothe inside faces of the plates 10, 12 to place an inward bias on theshaft 77 for maintaining the gears 68, 70 in engagement with theirrespective meshing gears.

A cylindrical pallet member 80 rotatably mounted on the end plates 10,12 similarly to the aforementioned gears, has axially extending palletpins 82 adapted in the usual manner for controlling the rate of angularmovement of the ratchet 64 and therefore of the shaft 40 when the gearsector 50 is in mesh with the gear 74. The mass of the pallet member 80and the drive ratio through the gears 66, 68, 70, 72, 74 and 50determine the rate of angular movement of the shaft and can be selectedas desired. In the shown embodiment, the gear sector 50 is positionedfor meshing with the gear 74 during approximately the first 60 degreesof forward movement of the shaft 40 from its reverse stop, with the timeof movement being approximately seconds.

In operation, the shaft is manually rotated in the reverse directionuntil the reverse stop 56 engages the tang 60. Through the last 60degrees of this reverse movement, the gear sector meshes with the gear74 to drive it and the gear 72 in the counterclockwise direction, asseen in FIG. 1. Because the ratchet 64 is restricted from movement inthe reverse direction by the pins 82, the counterclockwise movement ofthe gear 72 (as seen in FIG. 1) moves the gears 68, 70 laterallyoutwardly to disconnect the gear train, and thereby allow for completionof the winding of the drive shaft. The mechanism may then be retained inthe ready or wound position as by a control pin 83 inserted through aguide bushing 85 mounted on the plate 10 and through one of theangularly spaced openings 87 in the escapement ratchet.

Upon withdrawal of the control pin 83, the escapement under the bias ofthe mainspring effects control of the angular movement of the shaft 40during the first degrees of forward angular movement of the shaft due tothe engagement of the gear sector 50 with the pinion 74. Upontermination of the engagement of the gear sector 50 with the pinion 74,the drive shaft 40 is rotated forwardly at a relatively high rate by theforce of the mainspring 42 through an angle of 120 degrees, an angletwice the angle of regulated or restrained motion.

For operatively connecting the bolts 20, 22 with the drive shaft 40there are mounted on the drive shaft within the openings 30 of the bolts20, 22 a pair of identical oppositely extending earns 90, 92,respectively. As seen in FIGS. 3 through 6, the end of the shaft 40 ismachined to provide flats, and the cams 90, 92 have correspondingslotted openings receiving the shaft to provide a drive connectiontherewith. A spacer 93 is located between the cams and the outer end ofthe shaft 40 is upset to rivet the cams to the shaft.

The fully wound or ready position of the drive shaft 40 is shown inFIGS. 4 and 6, with the bolts 20, 22 in their extended lockingpositions. The earns 90, 92 have diametrically opposed action lobes 94of partially circular shape which engage the bolt shoulders 32 formaintaining the bolts in their extended locking positions and so thatthe lines of contact between the lobes 94 and the shoulders 32 are in aplane with the shaft axis that is parallel to the axes of rectilinearmovement of the bolts. Therefore, any forces which are directed inwardlythrough the bolts to the cams will not create a coupling moment on thedrive shaft and, as they are in direct opposition, will function tocounteract each other to reduce or eliminate the resultant force on thedrive shaft. Similarly, with the drive shaft in the fully released orunwound position, as shown in FIGS. 3 and 5, with the bolts in theirretracted positions, any forces directed through the cams and bolts arein direct opposition in a plane parallel to the axes of rectilinearmovement of the bolts.

A retaining lobe 96 on the earns 90, 92 has a partially circular camedge coaxial with the shaft 40 with a radius slightly less than theradius of the apex of the cam edge of the action lobe 94. Consequently,upon forward angular movement of the shaft 40 from the wound positionshown in FIGS. 4 and 6, after the action lobe 94 moves out of engagementwith the shoulder 32, the retaining lobe 96 is normally out of contactwith the shoulder 32 but, nevertheless, provides for preventingsubstantial inward movement of the bolts to retain them in lockingengagement with the casing 15.

In operation, the shaft 40 as aforementioned, will move an angle a ofsubstantially 60 degrees under the control of the escapement, at whichpoint the action lobes 94 have moved out of engagement with theshoulders 32, as seen in phantom in FIGS. 4 and 6. At that point theshaft 40 moves rapidly under the torque applied by the mainspring, firstan angle b of substantially 60 degrees prior to reengagement of theaction lobes with the bolts as further seen in phantom in FIGS. 4 and 6.During this interval the retaining lobes 96 ensure that the bolts aresufiiciently extended to lock the end plate or cap 14 to the casing.

The bolts 20, 22 are withdrawn during substantially the last 60 degreesof forward movement of the shaft, with initial contact by the actionlobes 94 with the bolts being in sliding engagement along the concaveshoulders 34 for providing gradual acceleration of the bolts and therebyminimize the wear and shock on the moving parts. With the completion ofthe forward movement of the shaft, as seen in FIGS. 3 and 5, the actionlobes 94 have fully retracted the bolts to release the latch,

It can therefore be seen that the latching mechanism of the presentinvention provides for automatic actuation of the sliding bolts after apreselected time interval, and is readily adapted for automaticunlatching of the cap of an aerospace vehicle. Additionally because ofthe new and novel relationship of parts, the operation of the latchingmechanism of the present invention provides highly reliable operationwith a compact assembly of parts related for minimum wear and shock.

As will be apparent to persons skilled in the art, various modificationsand adaptations of the structure above described will become readilyapparent without departing from the spirit and scope of the invention,the scope of which is defined in the appended claims.

I claim:

1. A latching mechanism comprising a pair of overlying elongated fiatbolt members mounted in slidable engagement for longitudinal parallelrectilinear movement, said bolt members having overlying slot openingsdefined in part by pairs of opposed longitudinally spaced straight edgesrespectively, extending substantially normal to the axes of rectilinearmovement of the bolt members and longitudinally extending opposedconcave edges at least at one lateral end thereof, an operating shaftmounted for forward and reverse rotatable movement about an axisextending substantially normal to the fiat bolt members andsubstantially normal to their axes of rectilinear movement, stop meansfor limiting the angular movement of the-operating shaft in the reverseangular direction, and am. m n On. the operating shaft including a pairof diametrically opposed convex action cam parts engageable With theopposed concave edges and with the pairs of opposed straight edges forextending the bolt members in opposite rectilinear directions uponreverse angular displacement of the operating shaft to its reverse limitand for withdrawing the bolt members inwardly upon forward angulardisplacement of the operating shaft from its reverse limit, said convexaction ca-m parts with the operating shaft at its reverse limit engagingthe straight edges of the bolt members along a line through the axis ofthe operating shaft parallel to the axes of rectilinear movement of thebolt members.

2. A latching mechanism comprising a pair of elongated bolt membersslidably mounted for longitudinal parallel rectilinear movement, a latchoperator mounted for rotatable movement about an axis extendingsubstantially normal to the axes of movement of the bolt members, cammeans on the latch operator providing a pair of convex camming parts,said bolt members having pairs of longitudinally spaced opposed straightfollower edges ex tending normal to their axes of movement andengageable by the convex camming parts respectively to extend andwithdraw the bolt members, said convex camming parts being diametricallyrelated for engagement with opposed straight edges on the bolt membersfor simultaneous Withdrawal and extension of the bolt members, forwardand reverse limit means for restricting the angular freedom of movementof the latch operator in forward and reverse angular directions, meansproviding a torsional bias on the latch operator for moving the latchoperator from its reverse limit position to its forward limit position,and means for restraining the rate of angular movement of the latchoperator by the torsion bias during a first angle portion only of itsforward angular displacement from its reverse limit position, saidconvex camming parts being oriented to engage the opposed straight edgesof the bolt members to withdraw the bolt members during the forwardangular displacement of the latch operator and after a forward angulardisplacement of the latch operator from its reverse limit position Whichis greater than said first angle portion whereby the latch operator maybe accelerated by the torsional bias to provide snap withdraw-a1 of thebolt members.

3. The latching mechanism of claim 1 wherein the means restraining therate of angular movement of the latch operator comprises an escapement,and a rotatable gear and gear sector in mesh during the angle ofrestrained movement.

4. The latching mechanism of claim 1 wherein the restrained angle ofmovement is no greater than one-half of said angular freedom ofmovement.

5. A mechanism for latching a cap to an open ended housing comprising apair of overlying bolt members slidably mounted on the cap for parallelrectilinear movement into latching engagement with the housing, saidboit members having overlying slot openings defined in part by pairs ofopposed straight edges respectively extending substantially normal tothe axes of movement of the bolt members, a latch operator mounted forrotatable movement about an axis extending normal to the axes ofmovement of the bolt members between reverse and forward limitpositions, cam means on the latch operator including a pair of firstdiametrically opposed convex camming parts within the slot openings ofthe bolt members engageable with the pairs of opposed straight edgesrespectively for operating the bolt members in opposite rectilineardirections, said first convex camming parts with the latch operator inits reverse limit position being engageable with opposed edges of thebolt members respectively along a line through the axis of the operatorwhich is parallel to the axes of rectilinear movement of the boltmembers, a generally helical mainspring operatively connected to thelatch operator providing a forward torsional bias thereon, escapementmeans for restraining the rate of forward angular movement of the latchoperator, and disengageable gear means including a gear sector on thelatch operator providing for disconnecting the escapement means from thelatch operator at a predetermined angle of the latch operator from itsreverse limit, said gear sector being oriented on the latch operator sothat the opposed convex camming parts are at positions intermediate thepairs of opposed edges respectively With the latch operator at saidpredetermined angle.

6. The mechanism of claim 5 wherein the cam means further includes asecond pair of diametrically opposed convex camming parts 'angularlyspaced from said first diametrically opposed camming parts and having amaximum radius less than the maximum radius of the first diametricallyopposed camming parts.

7. A mechanism for latching a cap to an open ended housing comprising apair of overlying bolt members slidably mounted on the cap for parallelrectilinear movement into latching engagement with the housing, saidbolt members having overlying slot openings defined in part by pairs ofopposed edges extending substantially normal to the axes of movement ofthe bolt members, :a latch operator mounted for rotatable movement aboutan axis extending normal to the axes of movement of the bolt members,cam means on the latch operator including a pair of diametricallyopposed camming parts within the slot openings of the bolt membersengageable with the opposed edges for operating the bolt members inopposite directions, a generally helical mainspring operativelyconnected to the latch operator providing a forward torsional biasthereon, escapement means for restraining the rate of forward angularmovement of the latch operator, and disengageable gear means including agear sector on the latch operator operatively connecting the escapementmeans with the latch operator, said cam means and gear sector beingangularly oriented on the latch operator so that the opposed cammingparts are out of engagement with the opposed edges upon disengagement ofsaid gear means, and forward and reverse stop means limiting angularmovement of the latch operator to 180 degrees, said stop means beinglocated so that, with the latch operator at its full forward and reversepositions, the said opposed camming parts engage the opposed edges alonga line through the axis of the latch operator parallel to the axes ofmovement of the bolt members.

References Cited by the Examiner UNITED STATES PATENTS 564,813 7/1896Worthen 29237 1,026,207 5/l1912 Johnson 29237 2,199,163 4/1940 Quady46-86 2,600,350 6/1962 Webster et al 267 X OTHER REFERENCES ProductEngineering, vol. 32, No. 29, Frederick Marich, Mechanical Timers, July17, 1961, pages 54-56.

JOSEPH D, SEERS, Primary Examiner.

M. I-IENSON WOOD, JR., Examiner.

1. A LATCHING MECHANISM COMPRISING A PAIR OF OVERLYING ELONGATED FLATBOLT MEMBERS MOUNTED IN SLIDABLE ENGAGEMENT FOR LONGITUDINAL PARALLELRECTILINEAR MOVEMENT, SAID BOLT MEMBERS HAVING OVERLYING SLOT OPENINGSDEFINED IN PART BY PAIRS OF OPPOSED LONGITUDINALLY SPACED STRAIGHT EDGESRESPECTIVELY, EXTENDING SUBSTANTIALLY NORMAL TO THE AXES OF RECTILINEARMOVEMENT OF THE BOLT MEMBERS AND LONGITUDINALLY EXTENDING OPPOSEDCONCAVE EDGES AT LEAST AT ONE LATERAL END THEREOF, AN OPERATING SHAFTMOUNTED FOR FORWARD AND REVERSE ROTATABLE MOVEMENT ABOUT AN AXISEXTENDING SUBSTANTIALLY NORMAL TO THE FLAT BOLT MEMBERS ANDSUBSTANTIALLY NORMAL TO THEIR AXES OF RECTILINEAR MOVEMENT, STOP MEANSFOR LIMITING THE ANGULAR MOVEMENT OF THE OPERATING SHAFT IN THE REVERSEANGULAR DIRECTION, AND CAM MEANS ON THE OPERATING SHAFT INCLUDING A PAIROF DIAMETRICALLY OPPOSED CONVEX ACTION CAM PARTS ENGAGEABLE WITH THEOPPOSED CONCAVE EDGES AND WITH THE PAIRS OF OPPOSED STRAIGHT EDGES FOREXTENDING THE BOLT MEMBERS IN OPPOSITE RECTILINEAR DIRECTIONS UPONREVERSE ANGULAR DISPLACEMENT OF THE OPERATING SHAFT TO ITS REVERSE LIMITAND FOR WITHDRAWING THE BOLT MEMBERS INWARDLY UPON FORWARD ANGULARDISPLACEMENT OF THE OPERATING SHAFT FROM ITS REVERSE LIMIT, SAID CONVEXACTION CAM PARTS WITH THE OPERATING SHAFT AT ITS REVERSE LIMIT ENGAGINGTHE STRAIGHT EDGES OF THE BOLT MEMBERS ALONG A LINE THROUGH THE AXIS OFTHE OPERATING SHAFT PARALLEL TO THE AXES OF RECTILINEAR MOVEMENT OF THEBOLT MEMBERS.